Seats having synthetic foam cushions are widely employed in a variety of applications and as a foam cushion, in itself, has little structural strength it is common to use a support or pan to receive and support the cushion and provide the necessary resistance to cushion deformation as weight is applied to the cushion. Seats used with tractors, garden tractors, lawn mowers and industrial equipment commonly consist of a metal pan having a bottom portion, and often a back portion, which receives the foam cushion, the cushion usually being covered by vinyl sheeting or the like.
In most constructions, particularly with agriculturally related or industrial applications, the pan is formed of stamped sheet steel, and inserts are located within the cushion having nuts or other threaded type connectors wherein fasteners extend through the pan and attach the cushion thereon. Cushions may also be attached to the pan by welts or other binding structure which interconnects the peripheries of the pan and cushion, and it is known to use foam cushions in conjunction with synthetic plastic pans of a molded configuration. Typical examples of such constructions are shown in U.S. Pat. Nos. 3,281,185; 3,521,929; 4,792,189 and 4,834,458. In known seat constructions using foam cushions with synthetic plastic pans the cushions are not usually readily removable from the pans and replacement of the cushions is not easily accomplished.
In U.S. Pat. No. 4,836,609 a combination foam cushion and steel pan unit is disclosed wherein the cushion may be readily releasably removed from the pan, and this patent also discloses the use of hook and loop fastener elements for releasably mounting the cushion on the pan. However, the fastener elements are not molded into the pan and adherence of the fastener elements to the pan is a problem.
Seats utilizing foam cushions depend, to a large extent, upon the resiliency of the foam to provide cushioning and damping of vibrations. Spring members of various types have been used in combination with seats employing foam cushions, but such seats are relatively complex and of high cost. As shown in U.S. Pat. No. 4,353,869 a resilient suspension for foam cushions may be incorporated into a seat bottom of relatively limited vertical dimension, but such spring elements are separate from the basic seat support structure and require complex secondary operations and assembly with respect to the manufacture of the complete structure.
It is an object of the invention to provide a combination foam cushion and pan construction wherein both the cushion and pan are formed of a synthetic plastic material and quick release fasteners are interposed between the cushion and pan to permit ready replacement of the cushion.
Another object of the invention is to provide a foam cushion and pan seat assembly which does not require a welt or clinch element between the pan and seat and wherein an attractive transition between the pan periphery and the cushion is provided which requires no secondary assembly procedures.
A further object of the invention is to provide a foam cushion and pan assembly wherein both cushion and pan are formed of a synthetic plastic material and releasable fastener elements are molded into the pan and readily affixed to cushion structure minimizing assembly time.
Yet an additional object of the invention is to provide seat structure utilizing a foam cushion and a synthetic plastic cushion supporting pan wherein spring elements are homogeneously defined within the pan of the pan material, such spring elements aiding in the support of weight imposed upon the seat and reducing the transmission of vibrations from the pan to the cushion.
In the practice of the invention the seat pan includes bottom and back portions angularly related to each other, preferably homogeneously formed of a molded synthetic plastic material. The foam cushion may also include bottom and back portions releasably mounted upon and superimposed over the corresponding pan portions. The cushion portions include a rigid synthetic plastic insert remotely located from the cushion weight supporting surface as to be located adjacent the pan portions, and releasable fastener structure mounts the cushion upon the pan.
Preferably, the fastener is of the hook and loop element type available under the trademark VELCRO and one of the elements is molded into the synthetic plastic pan, while the other element is inserted into a hole formed in the cushion insert. Cushion replacement is readily achieved by the consumer by merely pulling the cushion away from the pan to release the fastener elements.
The pan peripheral configuration is such as to eliminate the need for a welt or clinch at the pan periphery to associate with the cushion, and the construction of the seat provides a clean unitary appearance.
The pan includes a periphery flange region generally disposed in the direction of the cushion which encompasses the region of the cushion disposed toward the pan and the size of the cushion is slightly greater than the pan peripheral flange dimension such that the seat periphery extends over the pan edge producing a quality appearance and eliminating pan edge shielding structure.
The use of a plurality of loop end hook element fasteners permits the cushion to be accurately and quickly assembled to the pan at the factory, and cushion replacement is readily achieved by the user without special skills or tools as the cushion can be pulled from the pan and a new cushion installed merely by locating the cushion relative to the pan and applying a compressive force to the cushion.
The central region of the pan bottom portion may be provided with a plurality of homogeneous spring members in the form of a plurality of resilient bands or strips homogeneously defined of the synthetic plastic material of the pan bottom portion which extend upwardly in a bowed convex configuration from the general plane of the pan bottom portion. Such spring members are preferably formed with a sinuous configuration and are received within a recess defined on the inner surface of the cushion bottom portion wherein the spring members are capable of deflection under the weight of the seat occupant to augment the damping and suspension action of the cushion bottom portion without adding significant cost to the assembled seat apparatus. The utilization of such homogeneous spring members requires no second operations to the manufacturing process and provides the seat with improved cushioning and vibration damping characteristics at minimal cost.